Size-dependent phase transition temperatures of dispersed systems

A phase transition equation on the basis of the additional pressure on the curved surfaces of dispersed systems has been proposed, and the specific differential equations for various kinds of phase transitions of dispersed systems have been derived by the phase transition equation. Applying the fusion transition equations, the melting temperatures of Au and Sn nanoparticles have been calculated, and the predicted melting temperatures are in good agreement with the available experimental data. The results show that the phase transition equations can be used to predict the temperatures of phase transitions of dispersed systems and to explain the phenomenon of metastable states; the size of the dispersed phase has noticeable effect on the phase transition temperature; all temperatures of fusion, solidification, condensation, vaporization, sublimation and desublimation decrease with decreasing radius of the dispersed phase, but the bubble point temperature of a planar liquid increases with decreasing absolute value of radius of the bubbles; the depression of melting temperature for a nanowire is approximately half of that for a spherical nanoparticle with identical radius.